1 | // Licensed to the .NET Foundation under one or more agreements. |
2 | // The .NET Foundation licenses this file to you under the MIT license. |
3 | // See the LICENSE file in the project root for more information. |
4 | // =========================================================================== |
5 | // File: CeeSectionString.h |
6 | // |
7 | // =========================================================================== |
8 | |
9 | #ifndef CeeSectionString_H |
10 | #define CeeSectionString_H |
11 | |
12 | #include <ole2.h> |
13 | #include "ceegen.h" |
14 | |
15 | // This class is responsible for managing all the strings that have |
16 | // been emitted for the PE file. |
17 | |
18 | // This class manages the strings that are added to the .rdata section. |
19 | // It keeps track of each string that has been added using a hashtable. |
20 | // The hash table is effectively 2-dimensional. There is a large "virtual |
21 | // hash space" that is used to get a wide hash code distribution. The |
22 | // virtual hash space is mapped into a real hash table where each n |
23 | // hash values in the virtual space fall into a given hash bucket for |
24 | // real hash table size n. Within the bucket, elements are stored in a linked |
25 | // list in-order. When an virtual hash entry corresponds to a given bucket, |
26 | // that bucket is searched for the matching hash id. If not found, it is |
27 | // inserted, otherwise, the value is returned. The idea is that for smaller |
28 | // apps, there won't be a large number of strings, so that collisions are |
29 | // minimal and the length of each bucket's chain is small. For larger |
30 | // numbers of strings, having a large hash space also reduces numbers |
31 | // of collisions, avoiding string compares unless the hash codes match. |
32 | |
33 | struct StringTableEntry; |
34 | |
35 | class CeeSectionString : public CeeSection { |
36 | enum { MaxRealEntries = 100, MaxVirtualEntries = 10000 }; |
37 | StringTableEntry *stringTable[MaxRealEntries]; |
38 | |
39 | StringTableEntry *createEntry(__in_z LPWSTR target, ULONG hashId); |
40 | StringTableEntry *findStringInsert( |
41 | StringTableEntry *&entry, __in_z LPWSTR targetValue, ULONG hashId); |
42 | void deleteEntries(StringTableEntry *e); |
43 | #ifdef RDATA_STATS |
44 | int dumpEntries(StringTableEntry *e); |
45 | void dumpTable(); |
46 | #endif |
47 | |
48 | public: |
49 | ~CeeSectionString(); |
50 | CeeSectionString(CCeeGen &ceeFile, CeeSectionImpl &impl); |
51 | virtual HRESULT getEmittedStringRef(__in_z LPWSTR targetValue, StringRef *ref); |
52 | }; |
53 | |
54 | #endif |
55 | |
56 | |